Disc storage cassettes

ABSTRACT

A disc cassette includes a curved portion configured to hold multiple discs. A platform portion abuts the curved portion. A movable bale is configured to maintain discs securely in the disc cassette except when rotated off the discs.

BACKGROUND

Disc libraries may be used for archival storage, where access times ofminutes to hours are acceptable. Discs, such as optical storage discs,are stored within the disc libraries such that they are accessible by adisc retrieval unit (DRU) to move discs between storage locations andthe drives that read and write the data on the discs.

SUMMARY

Embodiments relate to storage of discs in disc storage systems. In oneembodiment, a disc cassette includes a curved portion configured to holdmultiple discs. A platform portion abutts the curved portion. A movablebale is configured to maintain discs securely in the disc cassetteexcept when rotated off the discs.

These and other features, aspects and advantages of the embodiments willbecome understood with reference to the following description, appendedclaims and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high performance optical storage system that may implement adisc cassette device, according to an embodiment;

FIG. 2 shows a disc cassette device in an empty state, according to anembodiment;

FIG. 3 shows the disc cassette device of FIG. 2 loaded with discs,according to an embodiment;

FIG. 4 shows a top view of the disc cassette device of FIG. 2 with asingle disc, according to an embodiment;

FIG. 5 shows a magnified view of the disc cassette device of FIG. 4 witha single disc, according to an embodiment;

FIG. 6 shows a view of horizontal disc access by a disc retrieval unit(DRU) to/from a disc cassette device, according to an embodiment;

FIG. 7 shows a view of vertical disc access by a DRU to/from a disccassette device, according to an embodiment;

FIG. 8 shows a disc cassette device placed in a mounting rail or track,according to an embodiment;

FIG. 9 shows a side view of disc cassette device placed in a mountingrail or track, according to an embodiment;

FIG. 10 shows a bottom perspective view of disc cassette device,according to an embodiment;

FIG. 11 shows another bottom perspective view of disc cassette device,according to an embodiment;

FIG. 12 shows a side view of the operation of a retaining bale of thedisc cassette device, according to an embodiment;

FIG. 13 shows a side view of a progressed operation of the retainingbale of the disc cassette device of FIG. 12, according to an embodiment;

FIG. 14 shows a side view of another progressed operation of theretaining bale of the disc cassette device of FIG. 13, according to anembodiment;

FIG. 15 shows a bottom view of the disc cassette device showing the balereturn spring, according to an embodiment;

FIG. 16 shows two disc cassette devices side-by-side in a mounting railor track, according to an embodiment;

FIGS. 17A-B show side views of another bale of the disc cassette deviceconfigured to receive a locking rod, according to an embodiment; and

FIGS. 18A-B show side views of still another bale of the disc cassettedevice configured to receive a locking rod, according to an embodiment.

DETAILED DESCRIPTION

The descriptions of the various embodiments have been presented forpurposes of illustration, but are not intended to be exhaustive orlimited to the embodiments disclosed. Many modifications and variationswill be apparent to those of ordinary skill in the art without departingfrom the scope and spirit of the described embodiments. The terminologyused herein was chosen to best explain the principles of theembodiments, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

One or more embodiments include a disc cassette device for holding discsin an optical robotic disc library, for storage and retrieval, etc. Inone embodiment, the disc cassette device: has an open structure thatminimally interferes with a disc retrieval unit (DRU) gripper device asit picks up or returns discs; holds closely spaced discs (disc pitchbetween 1.75 and 2 mm) in well-defined locations without contact betweenadjacent discs; has index features to allow the DRU to accurately aligna gripper device and a disc kicker device to a selected disc; providesfor the selected disc to be moved vertically by a small distance by adisc kicker device into the gripper jaw devices and then, once gripped,horizontally onto the DRU; is accurately aligned and secured to thewhole library with mounting features on its base; and securely retainsthe discs even if the unit is subjected to shock, vibration or othermotion, or if loaded disc cassettes are being moved into or out of thelibrary (e.g., from an enclosure, etc.). In one embodiment, the curvedportion of the disc cassette device stably retains discs at the lowestpoints of the curved disc slots, and any disc can exit the cassette by astraight horizontal motion after being vertically lifted from its restposition clear of the bottom surface of the disc slot of the horizontalportion of the disc cassette extending toward the DRU.

FIG. 1 is a high performance optical storage system (or robotic disclibrary) 100 that may implement a disc cassette device 150, according toan embodiment. In one embodiment, the high performance optical storagesystem 100 includes an enclosure 110, a moveable arm 120 connected to aDRU 125 that includes a disc gripper device, multiple optical discdrives 130, multiple optical disc-based media (discs) 140, disc cassettedevices 150, and tracks or mounting rails 160 and 165 that hold the disccassette devices 150 in place. In one embodiment, the enclosure 110provides a stable platform and protection from the environment. In oneexample, the enclosure includes filter material connected to coolingfans (not shown) and a top enclosure (not shown for internal viewing).In one embodiment, the enclosure may be sized as a typical 19-inch rackmounted device with rack mounting connectors. Depending on the space andenclosure size chosen, the enclosure 110 may have a greater capacity ofoptical disc drives 130, disc cassette devices 150, and thus, discs 140.In one example, the disc cassette devices 150 are placed within theenclosure 110 on either side (e.g., left and right sides). In oneexample, additional space for disc cassette devices 150 and discs 140 isavailable adjacent the disc drives 130 (e.g., towards the front of theenclosure 110). In wider enclosures, more disc drives 130 may bepositioned adjacent each other on the left and right side of theenclosure when more available space for disc drives 130 is available. Inone embodiment, the moveable arm 120 moves through motors and gears ontracks within the enclosure 110 to move the DRU 125 from the back of theenclosure 110 to the front of the enclosure 110. The DRU 125 is moveableto either side of the enclosure 110 to retrieve a disc 140 using thedisc gripper device for placement in a disc drive 130 or for replacementback to a disc cassette device 150. In other embodiments, otherconfigurations of stored discs 140, disc drives 130 and the DRU 125 maybe used.

FIG. 2 shows a disc cassette device 150 in an empty state, according toan embodiment. In one example, discs 140 with nominal thickness (e.g.,1.2 mm) are spaced apart by thin (˜0.4 mm) ribs 520 (FIG. 5) 1.5 mm highto give a disc pitch between 1.75 and 1.82 mm. The ribs 520 keepadjacent discs 140 from touching, with a disc pitch less than 166% ofthe disc thickness, and with the fixed portion of the disc cassettedevice 150 allowing any disc 140 to exit its disc slot 255 withoutimpediment by in-disc-plane straight-line motions over an angular rangeof more than 45° from the disc's 140 rest position, and more than 90°from a position displaced from its rest position by less than 18 mm.With that pitch range, a 39 inch deep, 4 U high library will have acapacity between 815-850 discs (e.g., assuming the unit has six (6)optical disc drives 130, FIG. 1). A bale 210 serves to retain the discsin the disc cassette device 150 slots 255 except when a disc is beingretrieved or returned. In one embodiment, the bale 210 may be optional.The inside edge of the disc cassette device 150 incorporates indexfeatures or teeth 510 (FIG. 5) with edges aligned with the centers ofthe slots 255 in the disc cassette device 150, and hence closely to thecenters of discs in those slots 255.

In one embodiment, the disc cassette device 150 holds the discscoaxially in a vertical orientation. In one embodiment, the ribs 520 aredesigned to limit lateral contact with a disc 140 surface to thatportion of the outer edge. The disc cassette device 150 has featuresthat allow the DRU 125 (FIG. 1) to be positioned to within +/−0.1 mm soa disc selector or kicker device of a DRU 125 can lift one disc 140 intoa disc gripper device without disturbing adjacent discs 140. The disccassette device has additional features referred to as mounting rail ortrack connectors 260, 265 and 270, 275 that position it with respect toa mounting rail or track 160/165 (FIG. 1) or 810 (FIG. 8) on theenclosure 110 bottom portion. In one embodiment, the track connectors265 and 270 have a “dove tail” feature that fits within the mountingrail or track portions 165 and 160, respectively. In one example, themounting rail or track connectors are spring-like or flexible forgripping the mounting rails or tracks 160/165 or 810.

In one embodiment, the disc cassette device 150 contacts the outer rimof the disc 140 over an angle spanning substantially less than 180degrees when the disc is at home in a disc cassette device 150. The disccassette device 150 has a shorter lip 230, and a taller lip 280. Asdescribed, a combination of gravity and friction hold the discs 140 inplace. In one embodiment, the disc cassette device 150 may be formedthrough injection molding or similar techniques. In one embodiment,drafted surfaces allow the disc cassette device 150 to be injectionmolded. In one example, multiple drafted surfaces provide rigidity tothe bottom of the disc cassette device 150. In one embodiment, thesurface area of the drafted surfaces on the bottom of the disc cassettedevice 150 is greater than the surface area of the ribs 520 (FIG. 5),allowing the ribs 520 to release from the injection mold prior to thebottom of the disc cassette device 150 releasing from the injectionmold. In one example, the ribs 520 and slots 255 are devoid of ejectorpin marks.

FIG. 3 shows the disc cassette device 150 fully loaded with discs 140,according to an embodiment. In one embodiment, the bale 210 may bespring loaded (e.g., with return spring 1010, FIG. 15) and holds thediscs 140 in place to prevent movement during operation of the DRU 125(FIG. 1), loading and unloading the disc cassette device 150 from anenclosure 110, etc.

FIG. 4 shows a top view of the disc cassette device 150 with a singledisc 140 loaded, according to an embodiment. In one example, the discgripper device of the DRU 125 accesses the disc 140 that is pushed orkicked vertically by a disc kicker of the DRU.

FIG. 5 shows a magnified view of the disc cassette device 150 of FIG. 4with a single disc 140, according to an embodiment. The ribs 520 formthe slot 255 for holding the discs 140 in place and from contacting oneanother. The index features or teeth 510 enable precise DRU 125alignment to discs 140 based on using an optical sensor. In oneembodiment, the index features 510 positions are precisely related tothe positions of the disc slots 255 defined by the ribs 520. In oneexample, the index features 510 are twice as wide as the disc pitch,positioned such that each edge of each index feature 510 or tooth can beassociated with the center of a disc slot 255.

FIG. 6 shows a view 600 of horizontal disc access by a DRU 125 with adisc gripper device 610 to/from a disc cassette device 150, according toan embodiment. In one embodiment, a disc 140 is retrieved from thecassette device 150 with minimal motion and mechanical interference. Adisc 140 in the disc gripper device 610 (that is about 8 mm higher thanthe discs 140 in the disc cassette device 150) is moved onto or off ofthe DRU by a straight horizontal motion. The bottom of the disc 140 isguided by the horizontal ribs 520 (FIG. 5) on the left edge of the disccassette device 150 as it enters or leaves a guide slot on the DRU. Inone example, the ribs 520 and surface at their base beyond the 28° point(extending towards the front of the disc cassette device 150) arestraight and horizontal. With this geometry, a typical 120 mm diameterdisc held in the disc gripper device 610 8 mm higher than the discs inthe cassette will clear the surface at the base of the horizontal ribs520 by 1 mm, allowing the disc to be moved horizontally onto or off ofthe DRU without interference. In one example, the horizontal ribs 520prevent motion perpendicular to the disc's 140 surface and preventcontact with adjacent discs 140 as the bottom edge of the disc 140enters or leaves the end of the DRU guide slot adjacent to the cassettedevice 150. In one example, a bale 210 is pushed by an arm 126 of theDRU 125 to move the bale 210 off of the disc or discs 140 to enableretrieving and replacing discs 140 from/to the disc cassette device 150.

FIG. 7 shows a view 700 of vertical disc access by a DRU disc gripperdevice 610 to/from the disc cassette device 150, according to anembodiment. In one example, to retrieve or return a disc 140, the discgripper device 610 is aligned with a disc cassette device 150 slot 255and positioned above the disc cassette device 150. The disc 140 is movedvertically into or out of the disc gripper device 610 jaw devices by thecombination of forces provided by the disc kicker 710 on the left andthe vertical back wall of the disc cassette device 150 to the right. Thevertical ribs 520 on the back wall of the disc cassette device 150 alsoguide the disc 140 into or out of the disc gripper device 610 jawdevices and prevent contact with adjacent discs 140. Discs 140 in theirresting positions contact the cassette over an angular sector ofapproximately 118°, spanning from the back-most point of the disc 140,down to its bottom point, and continuing up approximately 28° further.The disc cassette device 150 inside wall and ribs 520 above the disc 140back-most point are straight and vertical.

In one example, the disc kicker 710, in combination with the verticaldisc cassette device 150 back wall surface, moves the disc vertically 8mm into the gripper device 610 jaw devices. The disc cassette device 150vertical back wall ribs 520 constrain the disc 140 in a verticalposition during this motion, guiding the disc 140. Discs 140 beingreturned to the disc cassette device 150 can be dropped vertically intothe slots 255, or lowered using the disc kicker 710 of the DRU 125.

FIG. 8 shows a view 800 of the disc cassette device 150 placed in amounting rail or track 810, according to an embodiment. In oneembodiment, disc cassette devices 150 are accurately and reproduciblylocated with respect to each other and the library by features that reston and interlock with the mounting rail or track 810.

FIG. 9 shows a side view 900 of disc cassette device 150 placed in amounting rail or track 810, according to an embodiment. In oneembodiment, the horizontal portions of disc cassette device 150 bottomrest on the mounting rail or rack 810 to position the disc cassettedevice 150 vertically while wedged-shaped springs or flexible fingers(the track connectors 265) press the disc cassette device 150 down andto the right, and wedge-shaped fingers (the track connectors 270) thatare non-flexible fix the disc cassette device's 150 horizontal positionand rotational orientation. In one example, the wedged-shaped fingersare lodged in mating grooves in the mounting rail or rack 810. In oneexample, the wedged-shaped fingers have flat coupling surfaces and rowsof the wedged-shaped fingers are disposed on a bottom side of the disccassette device 150. In one embodiment, the wedged-shaped fingers areconfigured so that the coupling surface is pressed against the topsurface of the mounting rail or rack 810 by the pressure of thewedged-shaped finger surfaces against mating surfaces in dovetail slotscut in the mounting rail or track 810, thus accurately defining the disccassette device's 150 vertical and lateral positions and its rotationalorientation.

FIG. 10 shows a bottom perspective view 1000 of the disc cassette device150, according to an embodiment. FIG. 11 shows another bottomperspective view 1100 of the disc cassette device 150, according to anembodiment. In one example, the horizontal reference surfaces 1110 andthe wedged-shaped fingers (the track connectors 265 and 270) thatposition the disc cassette device 150 are shown from the bottom view.The back wedged-shaped fingers (track connectors 265) are longer andhave more compliance, while the front wedged-shaped fingers (trackconnectors 270) are shorter and much stiffer. This arrangement reducesuncertainty in the disc cassette device 150 lateral and angularpositions, since they are essentially controlled by the stifferwedged-shaped fingers. The disc cassette device 150 retains the abilityto slide along the mounting rail or track 810 (FIG. 8) and multiple disccassette devices 150 may be loaded onto the mounting rail or track 810adjacent to one another. In one embodiment, locking devices may be usedat the beginning and end of the row of disc cassette devices 150 to fixtheir positions along the mounting rail or track 810, and thus fully fixtheir positions in the library. In one example, the bale 210, axle 1020,and bale return spring 1010 are viewable. The bale return spring 1010provides for the bale 210 to be moved by the DRU 125 (FIG. 1) and returnto its resting or disc locking/holding position. In one example, thebale 210 is configured to rotate on an axis below the rib 520 (FIG. 5)adjacent pairs and to maintain a disc-retention position based on thereturn spring 1010.

FIG. 12 shows a side view 1200 of the operation of a retaining bale 210of the disc cassette device 150, according to an embodiment. In oneexample, the disc 140 on the gripper device 610 of the DRU 125 isaligned with an empty slot (e.g., slot 255, FIG. 2) in the disc cassettedevice 150.

FIG. 13 shows a side view 1300 of a progressed operation of theretaining bale 210 of the disc cassette device 150 of FIG. 12, accordingto an embodiment. In one example, the gripper device 610 moves the disc140 towards the disc cassette device 150, contacting the bale 210.

FIG. 14 shows a side view 1400 of another progressed operation of theretaining bale 210 of the disc cassette device 150 of FIG. 13, accordingto an embodiment. In one example, the gripper device 610 has moved tothe drop-off position over the disc cassette device 150 with the bale210 moved fully back.

FIG. 15 shows a bottom view 150 of the disc cassette device 150 showingthe bale return spring 1010 and the bale axle 1020, according to anembodiment.

FIG. 16 shows two disc cassette devices 150 side-by-side in a mountingrail or track 810, according to an embodiment. In one example, the armsof the bale 210 are recessed into the disc cassette device 150 sides sothat bales 210 on adjacent disc cassette devices 150 do not interferewith one another when disc cassette devices 150 are tightly pressedagainst each other.

FIGS. 17A-B show side views 1700 of another bale 1710 of the disccassette device 150 configured to receive a locking rod through the bale1710 and the center hole of the discs 140, according to an embodiment.In one example, a locking rod prevents bale 1710 rotation, holding it inposition to retain all of the discs 140 in the disc cassette device 150.This feature is useful for transport, loading, and unloading of disccassette devices 150 partially or fully loaded with discs 140.

FIGS. 18A-B show side views 1800 of still another bale 1810 of the disccassette device 150 configured to receive a locking rod, according to anembodiment. In one example, a locking rod prevents bale 1810 rotation,holding it in position to retain all of the discs 140 in the disccassette device 150. This feature is useful for transport, loading, andunloading of disc cassette devices 150 partially or fully loaded withdiscs 140.

References in the claims to an element in the singular is not intendedto mean “one and only” unless explicitly so stated, but rather “one ormore.” All structural and functional equivalents to the elements of theabove-described exemplary embodiment that are currently known or latercome to be known to those of ordinary skill in the art are intended tobe encompassed by the present claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. section 112, sixthparagraph, unless the element is expressly recited using the phrase“means for” or “step for.”

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the embodiments.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the embodiments has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the embodiments in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the embodiments. Theembodiments were chosen and described in order to best explain theprinciples of the embodiments and the practical application, and toenable others of ordinary skill in the art to understand the embodimentsfor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A disc cassette comprising: a curved portionincluding multiple ribs, wherein the ribs define multiple disc slots inthe curved portion that are configured to hold multiple discs in place,and the discs are spaced apart by the ribs; and multiple index featurespositioned on an inside edge of the curved portion, wherein the indexfeatures are configured to allow alignment of a kicker device of a discretrieval unit (DRU) to a disc of the disc cassette to lift the discinto a disc gripper device without disturbing one or more other discs ofthe disc cassette that are adjacent to the disc.
 2. The disc cassette ofclaim 1, wherein positions of the index features on the inside edge ofthe curved position are relative to positions of the disc slots.
 3. Thedisc cassette of claim 2, wherein each edge of each index feature isaligned with a center of a disc slot.
 4. The disc cassette of claim 3,wherein each index feature is twice as wide as a disc pitch that theribs provide to keep the discs from contacting one another.
 5. The disccassette of claim 1, further comprising: an optical sensor; wherein theindex features enable the alignment utilizing the optical sensor.
 6. Thedisc cassette of claim 1, wherein the index features are configured toallow the alignment of the kicker device to the disc within 0.1 mm.